U.S. patent number 5,698,422 [Application Number 08/369,630] was granted by the patent office on 1997-12-16 for toner and developer compositions.
This patent grant is currently assigned to Xerox Corporation. Invention is credited to Robert D. Bayley, Carol A. Fox, Bernard Grushkin, Thomas R. Hoffend, Guerino G. Sacripante.
United States Patent |
5,698,422 |
Sacripante , et al. |
December 16, 1997 |
Toner and developer compositions
Abstract
A toner composition comprised of a polyester resin with
hydrophobic end groups, pigment, optional wax, optional charge
additive, and optional surface additives.
Inventors: |
Sacripante; Guerino G.
(Oakville, CA), Bayley; Robert D. (Fairport, NY),
Fox; Carol A. (Farmington, NY), Hoffend; Thomas R.
(Webster, NY), Grushkin; Bernard (Pittsford, NY) |
Assignee: |
Xerox Corporation (Stamford,
CT)
|
Family
ID: |
23456240 |
Appl.
No.: |
08/369,630 |
Filed: |
January 6, 1995 |
Current U.S.
Class: |
430/109.4 |
Current CPC
Class: |
C08G
63/20 (20130101); G03G 9/08755 (20130101); G03G
9/08788 (20130101); G03G 9/08793 (20130101); G03G
9/0904 (20130101); Y10S 430/105 (20130101) |
Current International
Class: |
C08G
63/00 (20060101); C08G 63/20 (20060101); G03G
9/09 (20060101); G03G 9/087 (20060101); G03G
009/087 () |
Field of
Search: |
;430/109,110,904,120,124 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
3590000 |
June 1971 |
Palermiti et al. |
3681106 |
August 1972 |
Barns et al. |
4525445 |
June 1985 |
DeRoo et al. |
4533614 |
August 1985 |
Fukumoto et al. |
4833057 |
May 1989 |
Misawa et al. |
4863825 |
September 1989 |
Yoshimoto et al. |
4940644 |
July 1990 |
Matsubara et al. |
4957774 |
September 1990 |
Doi et al. |
4968575 |
November 1990 |
Matsumura et al. |
4973539 |
November 1990 |
Sacripante et al. |
5047305 |
September 1991 |
Uchida et al. |
5368970 |
November 1994 |
Grushkin |
5391452 |
February 1995 |
Sacripante et al. |
5466554 |
November 1995 |
Sacripante et al. |
5578409 |
November 1996 |
Kotaki et al. |
|
Foreign Patent Documents
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|
|
|
|
|
|
0170421 |
|
Feb 1986 |
|
EP |
|
0531146 |
|
Mar 1993 |
|
EP |
|
0686873 |
|
Jul 1994 |
|
EP |
|
4228157 |
|
Apr 1993 |
|
DE |
|
2207438 |
|
Feb 1989 |
|
GB |
|
Other References
Patent Abstracts of Japan, vol. 14, No. 223 (P-1046) [4166], 11 May
1990 & JP-A-02052362 (Tomoegawa), 21 Feb. 1990. .
Patent Abstracts of Japan, vol. 13, No. 205 (C-595) [3553], 15 May
1989, & JP-A-01 024827 (Mitsubishi), 26 Jan. 1989..
|
Primary Examiner: Lesmes; George F.
Assistant Examiner: Codd; Bernard P.
Attorney, Agent or Firm: Palazzo; E. O.
Claims
What is claimed is:
1. A toner composition consisting essentially of a polyester resin
containing hydrophobic end groups, colorant, wax, optional charge
additive, and surface additives, and wherein said polyester resin
with hydrophobic end groups is poly(1,2-propylene
terephthalate-co-diethylene terephthalate) end blocked with a
stearyl or stearate, poly(1,2-propylene terephthalate-co-diethylene
terephthalate-co-1,1,1-trimethylene propane terephthalate) end
blocked with a stearyl or stearate, poly(1,2-propylene
terephthalate) end blocked with a stearyl or stearate,
poly(1,2-propylene terephthalate-co-diethylene terephthalate) end
blocked with a lauryl or laurate, poly(1,2-propylene
terephthalate-co-diethylene terephthalate) end blocked with a cetyl
or palmitate, poly(1,2-propylene terephthalate-co-diethylene
terephthalate) end blocked with octoate,
poly(1,2-propyleneterephthalate-co-diethylene terephthalate) end
blocked with a palmitate, stearyl, lauryl, stearate, or laurate;
and mixtures thereof.
2. A toner composition consisting essentially of a polyester resin
with hydrophobic end groups, colorant, optional wax, optional
charge additive, and optional surface additives, and wherein the
polyester is poly(1,2-propylene terephthalate-co-diethylene
terephthalate) end blocked with a stearate group, and which
polyester possesses a weight number average molecular weight of
10,500 grams per mole and having a diethylene/1,2-propylene molar
ratio of 15:85, respectively.
3. A toner composition consisting essentially of a polyester resin
with hydrophobic end groups, colorant, optional wax, optional
charge additive, and optional surface additives, and wherein the
polyester is poly(1,2-propylene terephthalate-co-diethylene
terephthalate) end blocked with stearate, and which polyester
possesses a weight average molecular weight of 15,600 grams per
mole and having a diethylene/1,2-propylene molar ratio of
15:85.
4. A toner composition consisting essentially of a polyester resin
with hydrophobic end groups, colorant, optional wax, optional
charge additive, and optional surface additives, and wherein said
polyester is poly(1,2-propylene terephthalate-co-diethylene
terephthalate-co-1,1,1 -trimethylene propane terephthalate) end
blocked with stearate, and which polyester possesses a weight
average molecular weight of 41,700 grams per mole and having a
diethylene/1,2-propylene molar ratio of 25:75.
5. A toner composition consisting essentially of a polyester resin
with hydrophobic end groups with about 4 to about 24 carbon atoms,
colorant, optional wax, optional charge additive, and optional
surface additives, and wherein said polyester is poly(1,2-propylene
terephthalate-co-diethylene terephthalate-co-1,1,1-trimethylene
propane terephthalate) end blocked with stearate, and which
polyester possesses a weight average molecular weight of 38,300
grams per mole and having a diethylene/1,2-propylene molar ratio of
25:75.
Description
BACKGROUND OF THE INVENTION
The invention is generally directed to toner and developer
compositions, and more specifically, the present invention is
directed to developer comprised of a carrier, optionally a flow
aid, and a hydrophobic toner compositions containing polyester
resins wherein the end groups of the polyester resin are
predominately modified with hydrophobic moieties, which, for
example, impart or assist in imparting excellent low relative
humidity sensitivity to the toner particles and enable toners with
rapid admix characteristics. In embodiments, there are provided in
accordance with the present invention toner compositions comprised
of pigment particles, optionally a charge control agent, and resin
particles comprised of a polyester resin containing a hydrophobic
end group with, for example, from 6 to about 24 carbon atoms, such
as hexyl, lauryl, stearyl, cetyl, and the like, or an aryl such as
or benzyl, and the like. More specifically, in embodiments of the
present invention, there are provided a toner comprised of pigment
particles, optionally a charge enhancing agent, optionally a wax
component, and a polyester resin containing hydrophobic end groups,
and which polyester is illustrated by the formulas I through III
##STR1## wherein R is an alkylene group such as divalent ethylene,
propylene, butylene, ethyleneoxyethylene or a hydrocarbon with from
about 2 to about 24 carbon atoms, and preferably 2 to about 20
carbon atoms, a cyclohexylene or 1,4-dimethyl cyclohexylene group;
R' is an arylene group with from about 6 to about 14 carbon atoms
such as the divalent moieties phenylene, isophthalylene,
terephthalylene or phthalylene, an olefinic group such as vinylene,
methylvinylene, or an alkylene group such as ethylene, propylene,
butylene, pentylene, hexylene, and the like; X is an alkyl or aryl
group, such as hexyl, heptyl, octyl, lauryl, stearyl, or benzyl,
with from about 4 to about 24 carbon atoms; and n represents the
number of segments, such as from about 10 to about 300. The
polyester resin can be branched or crosslinked by employing
trifunctional or multifunctional reagents, such as
trimethylolpropane or pyromellitic acid, of from about 0.1 to about
6 mole percent based on the starting diacid or diester selected to
prepare the polyester resin, and can be represented in the above
formulas I through III by incorporating the branching segments, p,
q, r or s as illustrated by the formulas ##STR2## wherein R" is a
multivalent aromatic or aliphatic radical with from about 3 to
about 20 carbon atoms, such as the tri or tetravalent derivatives
of propane, butane, pentane, hexane, cyclohexane, heptane, octane,
benzene, naphthalene, anthracene, and the like; and p, q, r and s
represent the branching segment and in embodiments is from about
0.1 to about 6 mole percent based on the starting diacid or diester
used to make the resin and provided that the sum of segments n, p
and q is 100 mole percent of the polyester resin.
In embodiments, the present invention relates to the preparation of
a polyester resin, and wherein the hydroxyl and acid end groups of
the resulting polyester are minimized, and preferably avoided.
Polyester resins are known to contain acid and hydroxyl groups of
from about 20 to about 1,000 milliequivalents per gram of
polyester, usually present as end groups. It is believed that these
hydrophilic end groups cause the toner composites to have
tribocharging performance that is humidity sensitive. The ratio of
the triboelectric charge of the toner composites at low humidity to
that at high humidity is of from about 2.8 to about 4.5, and
usually from about 3.0 to about 3.5. To reduce the relative
humidity sensitivity of polyester based toners, the present
invention minimizes the hydrophilic end groups, such as hydroxyl or
acid moieties on the polyester resin, by capping the ends of the
polyester with hydrophobic groups, such as alkyl moieties, hence
resulting in toners with low humidity sensitivity such as from
about 1.0 to about 2.8 and preferably from about 1.0 to about 2.5.
A further embodiment of the present invention relates to the
preparation of a polyester resin with monofunctional monomers that
cap the ends of the polyester resin to result in the aforementioned
polyester resin with hydrophobic end groups, and wherein the
concentration of the monofunctional hydrophobic monomers is from
about 0.1 mole percent to about 4.0 mole percent based on the
starting diacid or diester used to make the resin, and thereby
controls the weight average molecular weight of from about 4,000
grams per mole to about 250,000 grams per mole, especially when
monofunctional monomers with a carbon chain length of from about 4
to about 24 are selected or wherein the use of bulkier monomers
such as 1,2-naphthalene ethanol, or phenylmethanol are
utilized.
The aforementioned toner composition and developer thereof, that is
toner mixed with a carrier, display a low relative humidity
sensitivity for the toners thereof, which is desired such that the
triboelectric charge is stable to changes in environmental humidity
conditions. Copiers and printers equipped with two component
developers, that is a toner as one component mixed with the carrier
as the other component, can exhibit a positive or negative
triboelectric charge with a magnitude of from about 5 microcoulombs
per gram to about 40 microcoulombs per grams. This triboelectric
charge permits the toner particles to be transferred to the latent
image of the photoreceptor with an opposite charge, thereby forming
a toned image on the photoreceptor, which is subsequently
transferred to a paper or a transparency substrate, and thereafter
subjected to fusing or fixing processes. In these development
systems, it is important for the triboelectric charge to be stable
under differing environmental humidity conditions such that the
triboelectric charge does not change by more than from about 5 to
about 10 microcoulombs per gram. A change of more than from about 5
microcoulombs per gram to about 10 microcoulombs per gram in
triboelectric charge of the toner developer can cause nonuniform
toned images or result in no toning of the photoreceptor, thus
unbalanced density or gray scale is observed in the developed
images, or no developed images at all result. Generally, humidity
ranges may differ from less than about 20 percent in dry regions to
more than about 80 percent in humid regions, and some geographical
regions may exhibit fluctuations of up to from about 50 to about 80
percent humidity level within the same day. In such climates, it is
important that the developmental triboelectric charge does not
change by more than from about 5 microcoulombs per gram to about 10
microcoulombs per gram. As toner resins generally represent from
about 80 percent to about 98 percent by weight of toner, the resin
sensitivity to moisture or humidity conditions should be minimized
thereby not adversely affecting the triboelectric charge
thereof.
A number of toner polymeric resins utilized as toner compositions,
such as for example styrene-acrylates, styrene-methacrylates,
styrene-butadienes and especially polyesters, contain from about
0.1 to about 2 percent by weight of moisture, and in some
instances, the moisture content of polyesters may change from about
0.1 to about 4 percent by weight at humidity levels ranging from
about 10 to about 100 percent, or more usually from about 20
percent to about 80 percent humidity. These changes in moisture
content of the resin may have a dramatic adverse effect on the
triboelectric charge of the toner and developer thereof. Relative
humidity sensitivity of toner is customarily measured by first
fabricating a toner comprised of a pigment, optional charge control
agent and a resin, then admixing the toner from about 3 percent by
weight to about 7 percent by weight with a carrier. The developer
composition is then equilibrated to various humidity levels in a
sealed chamber at controlled temperatures of 60.degree. F. at 20
percent RH and 80.degree. C. at 80.degree. F. for a period of about
48 hours. The triboelectric charge is then measured for the same
developer composition at different humidity levels and the results
analyzed by several methods, such as graphing the triboelectric
charge as a function of humidity level and observing the regions in
which dramatic changes occur. Another measuring method comprises
dividing the aforementioned graphical interpolation of tribo versus
humidity level in three regions, wherein region A is from about 0
to about 30 percent humidity, region B is from about 30 to about 65
percent humidity, and region C is higher than about 65 percent
humidity to about 100 percent. Since these measurements are
cumbersome and time consuming, there can be measured the
triboelectric charge after subjecting the toner developer
composition to two humidity levels, such as 20 percent relative
humidity and 80 percent relative humidity, and then calculating the
relative sensitivity by taking the triboelectric charge ratio of
the 20 to 80 percent relative humidity as follows ##EQU1## wherein
RH is the relative humidity.
Thus, if the relative humidity sensitivity is about 1.0, the toner
composition is considered humidity insensitive, whereas if the
humidity sensitivity is greater than about 3, the toner composition
is considered to be very humidity sensitive. It is generally
believed that toners prepared with a number of polymeric materials
exhibit relative sensitivity greater than 1.0, and in general,
styrene butadiene, or styrene acrylate based toners possess
humidity sensitivities greater than 1.0 and less than about 2.5,
whereas generally, polyester based toners possess a relative
humidity sensitivity of greater than 2.5 and less than about 5.
Hence, an advantage of the styrene-acrylate or styrene-butadiene
type binder resins for toners over that of polyesters is their
lower relative humidity sensitivity. Polyesters are known to
display advantages over styrene based resins, such as low fixing
temperatures of from about 120.degree. C. to about 140.degree. C.,
and nonvinyl offset properties. Therefore, there is a need for
toner compositions comprised of a resin which possess many of the
aforementioned advantages, such as low fixing temperature of from
about 120.degree. C. to about 140.degree. C., nonvinyl offset
properties, and in addition low sensitivity of tribocharging as a
function of relative humidity such that the ratio of triboelectric
charge at 20 percent and 80 percent RH is from about 1.0 to about
2.5. These and other advantages are attained in embodiments with
the toner compositions of the present invention comprised of a
pigment, optionally a charge control agent, and a modified
polyester resin wherein the end groups are hydrophobic moieties,
and which toner exhibits a low fixing temperature of from about
120.degree. C. to about 140.degree. C., nonvinyl offset properties,
and low relative humidity sensitivity, such as from about 1.0 to
about 2.5.
Additionally, the aforementioned toner compositions of the present
invention may contain waxes so that fuser stripping failure is
avoided or minimized. The present invention in embodiments is
directed to polyesters with hydrophobic end groups, wherein
specifically the hydrophobic end groups are from about 4 carbon
atoms to about 24 carbon atoms.
Furthermore, the presence of the hydrophobic end group monomers
provide an improved process for obtaining the aforementioned
polyesters. Specifically, the concentration of the monofunctional
monomer provides molecular weight control of the polyester product,
and its reproducibility. The process for the preparation of the
polyester resins of the present invention is known as a
condensation process or step polymerization. The condensation
process involves the addition of bifunctional monomers which result
in dimers, followed by the reaction of dimers with dimers to form
tetramers, or dimers with monomers to form trimers. The reaction
sequence then continues in that these dimers, trimers and tetramers
react with each other to form multiples thereof and known in the
art to be oligomers, which in turn react with other oligomers to
form the polyester. In this aforementioned kinetic scheme, the
degree of polymerization is achieved by terminating the reaction at
the desired point, hence it is time dependent. It is known that
obtaining a specific degree of polymerization by relying on the
time of the polymerization of the step reaction polymerization
process is very difficult. A method for controlling the degree of
polymerization is to adjust the composition of the reaction mixture
away from stoichiometric equivalence, by adding a nonvolatile
monofunctional reagent in the amount from about 0.1 mole percent to
about 4.0 mole percent based on the starting diacid or diester used
to make the resin. In the present invention, the monofunctional
monomers employed are the hydrophobic monomers. The degree of
polymerization can further be controlled by the amount of
monofunctional monomer utilized, hence limiting the degree of
polymerization as determined by its concentration such that the
total amount of end groups is proportional to the amount of
monofunctional monomer employed. This aids in the reproducibility
of the product by adjusting the amount of monofunctional monomer to
the desired limit of degree of polymerization, hence avoiding total
dependence on time of polymerization.
Also, the aforementioned toner compositions usually contain pigment
particles comprised of, for example, carbon black like REGAL
330.RTM., magnetites, or mixtures thereof, cyan, magenta, yellow,
blue, green, red, or brown components, or mixtures thereof thereby
providing for the development and generation of black and/or
colored images. The toner compositions of the present invention in
embodiments thereof possess excellent admix characteristics as
indicated herein, and maintain their triboelectric charging
characteristics for an extended number of imaging cycles, up to for
example 1,000,000 in a number of embodiments. The toner and
developer compositions of the present invention can be selected for
electrophotographic, especially xerographic, imaging and printing
processes, including color processes.
There is also a need for toners having low relative humidity
sensitivity, such as from about 1.0 to about 2.8 and preferably of
from about 1.0 to about 2.5 as calculated by Equation 1, and
wherein low minimum fixing temperatures are obtained, such as from
about 120.degree. C. to about 140.degree. C. with broad fusing
latitude such as from about 30.degree. C. to about 45.degree. C.
wherein the fusing latitude is considered the difference between
the minimum fixing temperature and the temperature at which the
toner offsets to the fusing member.
Certain polyester toner resins are known, reference for example
U.S. Pat. Nos. 3,590,000 and 4,525,445, which illustrate a linear
polyester comprised preferably of propoxylated bisphenol A and
fumaric acid, and available as SPAR II.RTM. from a number of
sources such as Atlas Chemical Company. There is also disclosed in
Japanese Laid Open Patents 44836 (1975), 37353 (1982), 109875
(1982) and 3031858-A (1991), and references therein a linear
polyester resin comprised of polybasic carboxylic acid, such as
derived from ethoxylated bisphenol A, cyclohexanedimethanol and
terephthalic acid. Further, there is disclosed in U.S. Pat. No.
4,533,614, and more specifically, U.S. Pat. Nos. 4,957,774 and
4,533,614 a linear polyester resin comprised of dodecylsuccinic
anhydride, terephthalic acid, alkyloxylated bisphenol A and
trimellitic anhydride as chain extenders.
Additionally, there is disclosed in U.S. Pat. No. 4,940,644, U.S.
Pat. No. 5,047,305, U.S. Pat. No. 4,049,447, and Canadian Patent
1,032,804 a linear polyester comprised of an amorphous aromatic
polyester derived from an arylene radical and diol, and
specifically resins such as poly(neopentyl-terephthalate) comprised
of terephthalate radical and neopentyl glycol. Also, there is
disclosed in U.S. Pat. No. 4,525,445 a toner composition comprised
of a linear polyester derived from fumaric acid, isophthalic acid
and propoxylated bisphenol. Further, other toner compositions are
known to contain linear polyester resins, such as those disclosed
in U.S. Pat. No. 4,968,575 a linear polyester blocked with rosin
compound; U.S. Pat. No. 5,004,664 a linear polyester prepared from
the ring opening polymerization of cyclic monomers; U.S. Pat. No.
5,057,392 a blend of resins comprised of a crystalline and
amorphous polyesters; and U.S. Pat. Nos. 4,543,313 and 4,891,293
wherein there are disclosed linear thermotropic liquid crystalline
polyester resins, the disclosures of which are totally incorporated
herein by reference. Other U.S. patents of interest disclosing, for
example, linear polyesters are U.S. Pat. Nos. 4,052,325; 3,998,747;
3,909,482; 4,4049,447; 4,288,516; 4,140,644; 4,489,150; 4,478,423;
4,451,837; 4,446,302; 4,416,965; 4,866,158; 5,153,301; 5,116,713;
5,043,242; 5,045,424; 5,049,646; 5,102,762; 5,110,977 and
4,837,394.
Compositions containing modified polyester resins with a polybasic
carboxylic acid are also known and disclosed in Japanese Laid Open
Nos. 44836 (1975); 3753 (1982) and 109875 (1982); and also in U.S.
Pat. No. 3,681,106, and more specifically branched or crosslinked
polyesters derived from polyvalent acids or alcohols are
illustrated in U.S. Pat. Nos. 4,298,672; 4,863,825; 4,863,824;
4,845,006; 4,814,249; 4,693,952; 4,657,837; 5,143,809; 5,057,596;
4,988,794; 4,981,939; 4,980,448; 4,960,664; 4,933,252; 4,931,370;
4,917,983 and 4,973,539. The resulting modified polyester resins by
branching or crosslinking improves the hot-offset resistance only
at the expense of the low fixing temperature performance. In some
of the aforementioned prior art references, there are disclosed
polyester resins wherein the end groups are either an acid group,
wherein acid numbers are reported, or hydroxyl groups. Therefore,
the polyester ends are hydrophilic and different from those of the
present invention wherein the polyester resins are modified to be
comprised mainly of hydrophobic end groups such that hydroxyl, or
acid content is minimized or avoided, and not present, at least to
a significant amount. The polyester resin with hydrophobic end
groups of the present invention reduces the relative humidity
sensitivity of the toners made from the resins, while still
retaining the favorable low fixing temperatures, such as from about
120.degree. C. to about 140.degree. C. and broad fusing latitude,
as well as excellent admix such as about 60 seconds or less.
To prevent fuser roll offsetting and to increase the fuser latitude
of toners, various modifications to toner compositions have been
proposed. For example, U.S. Pat. No. 4,513,074 discloses adding
waxes, such as low molecular weight polyethylene, polypropylene, to
toners to increase their release properties. To sufficiently
prevent offset, however, considerable amounts of such materials may
be required, resulting in the detrimental effect of toner
agglomeration, degradation in free flow properties, and
destabilization of charging properties.
There is illustrated in U.S. Pat. No. 5,391,452, the disclosure of
which is totally incorporated herein by reference, a toner
comprised of pigment particles, optionally a charge control agent
and a polyester resin comprised of poly(1,2-propylene diethylene
terephthalate) with hydroxyl end groups.
There is illustrated in U.S. Pat. No. 5,168,028 a negatively
chargeable toner for developing latent electrostatic images
comprising a binder resin, a coloring agent and a charge
controlling agent which comprises a fluorine-containing quaternary
ammonium salt. There are illustrated in U.S. Pat. No. 5,324,613
toners with hydroxy bis(3,5-ditertiary butyl salicylic) aluminate
monohydrate; U.S. Pat. No. 4,656,112 toners with a zinc complex
(E-84) of 3,5-ditertiary butyl salicylate; and U.S. Pat. No.
4,845,003 toners with a hydroxy carboxylic acid. The disclosures of
each of the aforementioned patents are totally incorporated herein
by reference.
There is illustrated in U.S. Pat. No. 5,466,554, the disclosure of
which is totally incorporated herein by reference, a toner
comprised of pigment particles, optionally a charge control agent,
and a polyester resin with hydrophobic end groups such as a silane
or fluorinated carbon, halogenated carbon and the like. The U.S.
Pat. No. 5,466,554 contains negatively charged end groups such that
negative developers can be attained without the use of a charge
control agent, however, such hydrophobic end groups are not alkyl
or aryl moieties.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide toner and
developer compositions wherein the polyester toner binder resin
contains hydrophobic end groups.
In another object of the present invention there are provided
negatively, or positively charged toner compositions useful for the
development of electrostatic latent images including color
images.
In yet another object of the present invention there are provided
negatively charged toner or positively charged toner compositions
containing polyester with hydrophobic end groups such as a
hydrocarbon or aromatic moiety of from about 4 carbon atoms to
about 24 carbon atoms.
Also, in another object of the present invention there are provided
developer compositions with negatively, or positively charged toner
particles, and carrier particles.
In yet a further object of the present invention there are provided
toners having triboelectric properties with low humidity
sensitivity such as, for example, from about 1.0 to about 2.5.
Also, in yet another objective of the present invention there are
provided toners having triboelectric properties with low humidity
sensitivity, such as for example, from about 1.0 to about 2.5, with
desirable admix properties of 15 seconds to 60 seconds as
determined by the charge spectrograph, and preferably 15 to 30
seconds.
Moreover, in another objective of the present invention there are
provided toners having triboelectric properties with low humidity
sensitivity with low minimum fixing temperatures such as from about
120.degree. C. to about 140.degree. C.
Also, in yet another objective of the present invention there are
provided toners having triboelectric properties with low humidity
sensitivity with broad fusing latitude, such as from about
30.degree. C. to about 45.degree. C.
Also, in yet another objective of the present invention there is
provided a method for reproducibly controlling the degree of
polymerization.
Furthermore, in yet another object of the present invention there
are provided toner and developer compositions that are useful in a
variety of electrostatic imaging and printing processes, including
color xerography, and wherein the admix charging times are less
than or equal to about 60 seconds.
These and other objects of the present invention can be
accomplished in embodiments thereof by providing toner compositions
comprised of pigment particles, and a polyester resin wherein the
end groups are hydrophobic. More specifically, the present
invention in embodiments is directed to toner compositions
comprised of pigment or dye, and a polyester having chemically
attached thereto end groups, such as an alkyl moiety comprised of a
hydrocarbon, especially alkyl, of from about 4 carbon atoms to
about 24 carbon atoms. Advantages of low humidity sensitivity,
rapid admix, appropriate triboelectric characteristics, and the
like are achieved with many of the aforementioned toners of the
present invention.
Examples of polyester resins with hydrophobic end groups that can
be selected include the polyesters with alkyl end groups of the
formulas illustrated herein such as poly(1,2-propylene
terephthalate-co-diethylene terephthalate) end blocked with
stearate, poly(1,2-propylene terephthalate) end blocked with
stearate, poly(1,2-propylene terephthalate-co diethylene
terephthalate) end blocked with laurate, poly(1,2-propylene
terephthalate-co-diethylene terephthalate) end blocked with cetate,
poly(1,2-propylene terephthalate-co-diethylene terephthalate) end
blocked with octoate, poly(1,2-propylene
terephthalate-co-diethylene terephthalate) end blocked with a hexyl
group, poly(1,2-propylene terephthalate-co-diethylene
terephthalate) end blocked with a dodecyl group, poly(1,2-propylene
terephthalate-co-diethylene terephthalate) end blocked with a decyl
group, poly(1,2-propylene terephthalate-co-diethylene
terephthalate) end blocked with a benzyl group, mixtures thereof,
and the like; and which display a number average molecular weight
of from about 2,000 grams per mole to about 100,000 grams per mole,
a weight average molecular weight of from about 4,000 grams per
mole to about 250,000 grams per mole, and polydispersity of from
about 1.8 to about 17, as measured by gel permeation
chromatography.
The polyester resin with the hydrophobic end groups selected for
the toner and developer compositions of the present invention, such
as the poly(1,2-propylene terephthalate-co-diethylene
terephthalate) end blocked with stearate, can be prepared by
charging a 1 liter Parr reactor equipped with a mechanical stirrer
and side condenser, a mixture of from about 0.9 to about 0.95 mole
of diester, such as dimethylterephthalate, from about 1.75 moles to
about 1.85 moles of a diol, such as 1,2-propanediol or diethylene
glycol or a mixture of the diols, containing from about 0.15 to
about 0.3 mole of diethylene glycol, from about 0.01 to about 0.1
mole percent of stearic acid, and from about 0.001 mole to about
0.05 of a condensation catalyst such as butyltin oxide. The reactor
is subsequently heated to 170.degree. C. for a duration of from
about 360 minutes to about 720 minutes with stirring at from about
10 revolutions per minute to about 200 revolutions per minute.
During this time, from about 1.7 moles to about 1.9 moles of
methanol byproduct can be collected through the condenser. The
reactor temperature is then raised to about 220.degree. C. and the
pressure is reduced to about 1 torr over a period of from about 2
hours to about 3 hours. The polymeric resin comprised of
poly(1,2-propylene terephthalate-co-diethylene terephthalate) end
blocked with stearate is then discharged through the bottom of the
reactor and cooled to room temperature.
In a specific embodiment, a polyester resin comprised of
poly(1,2-propylene terephthalate-co-diethylene terephthalate) end
blocked with stearate can be obtained by charging a one liter Parr
reactor equipped with a bottom drain valve, double turbine agitator
and distillation receiver with a cold water condenser with from
about 0.95 mole to about 1.05 mole of diester, such as
dimethylterephthalate, from about 0.60 to about 2.05 moles of diol
such as 1,2-propanediol, from about 0.01 to about 0.40 mole of a
second diol such as diethylene glycol, from about 0.001 to about
0.04 mole of monofunctional monomer such as stearic acid, and from
about 0.001 to about 0.05 mole of a catalyst such as tetrabutyl
titanate. The reactor is then heated to from about 150.degree. C.
to about 187.degree. C. with stirring for a duration of from about
3 hours to about 20 hours. Five tenths (0.5) to about 1 mole of
alcohol byproduct is collected in the distillation receiver
comprised of from about 80 percent to about 100 percent by volume
of methanol and from about 0 percent to about 20 percent by volume
of 1,2-propanediol as measured by an ABBE refractometer available
from American Optical Corporation. The mixture is then heated from
about 180.degree. C. to about 220.degree. C. and vacuum applied
slowly. While raising the reaction temperature from 180.degree. C.
to 220.degree. C., the pressure is reduced from atmospheric
pressure (760 torr) to about 0.01 torr. This stepwise increase in
temperature and reduction in pressure takes place over the course
of from about 1 to about 9 hours while collecting distillate.
Approximately 0.8 to about 1.5 mole of distillate are collected in
the distillation receiver comprised of a mixture of methanol and
glycol. The reactor is then purged with nitrogen to atmospheric
pressure. The resulting linear polyester resin is then discharged
through the bottom drain onto a container cooled with dry ice to
yield poly(1,2-propylene terephthalate-co-diethylene terephthalate)
end blocked with stearate. Variations of the above synthesis can be
used by those skilled in the art, such as introducing the
monofunctional monomer after the initial esterification.
Toners prepared with the polyester resins of the present invention
can be obtained by admixing and heating the polyester resin
particles such as poly(1,2-propylene terephthalate-co-diethylene
terephthalate) end blocked with stearate, pigment particles such as
magnetite, carbon black, or mixtures thereof, and preferably from
about 0.20 percent to about 5 percent of optional charge enhancing
additives, or mixtures of charge additives, and optionally wax in a
melt mixing device, such as the ZSK53 extruder available from
Werner Pfleiderer. After cooling, the toner composition is
subjected to grinding utilizing, for example, a Sturtevant
micronizer for the purpose of achieving toner particles with a
volume median diameter of less than about 25 microns, and
preferably from about 6 to about 12 microns, as determined by a
Coulter Counter. The toner particles can be classified by
utilizing, for example, a Donaldson Model B classifier for the
purpose of removing fines, that is toner particles less than about
4 microns volume median diameter.
Specific examples of diols utilized in preparing the aforementioned
polyesters of the present invention include diols or glycols such
as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol,
1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol,
1,2-pentylene glycol, 1,3-pentylene glycol, 1,4-pentylene glycol,
1,5-pentylene glycol, 1,2-hexylene glycol, 1,3-hexylene glycol,
1,4-hexylene glycol, 1,5-hexylene glycol, 1,6-hexylene glycol,
heptylene glycols, octylene glycols, decylene glycol, dodecylene
glycol, 2,2-dimethyl propanediol, propoxylated bisphenol A,
ethoxylated bisphenol A, 1,4-cyclohexane diol, 1,3-cyclohexane
diol, 1,2-cyclohexane diol, 1,2-cyclohexane dimethanol, mixtures
thereof, and the like; and these glycols are employed in various
effective amounts of, for example, from about 45 to about 55 mole
percent of the polyester product resin.
Specific examples of diacids or diesters utilized in preparing the
aforementioned polyesters include malonic acid, succinic acid,
2-methylsuccinic acid, 2,3-dimethylsuccinic acid, dodecylsuccinic
acid, glutaric acid, adipic acid, 2-methyladipic acid, pimelic
acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic
acid, phthalic acid, 1,2-cyclohexanedioic acid,
1,3-cyclohexanedioic acid, 1,4-cyclohexanedioic acid, glutaric
anhydride, succinic anhydride, dodecylsuccinic anhydride, maleic
anhydride, fumaric acid, maleic acid, itaconic acid, 2-methyl
itaconic acid, and dialkyl esters of these diacids and
dianhydrides, wherein the alkyl groups of the dialkyl ester are of
one carbon atom to about 5 carbon atoms and mixtures thereof, and
the like, and which component is employed, for example, in amounts
of from about 45 to about 55 mole percent of the resin.
Specific examples of polycondensation catalysts can include
tetraalkyl titanates, dialkyltin oxide such as dibutyltin oxide,
tetraalkyltin such as dibutyltin dilaurate, dialkyltin oxide
hydroxide such as butyltin oxide hydroxide, aluminum alkoxides,
alkyl zinc, dialkyl zinc, zinc oxide, stannous oxide, or mixtures
thereof; and which catalysts are selected in effective amounts of
from about 0.01 mole percent to about 5 mole percent based on the
starting diacid or diester used to make the resin.
Examples of monofunctional hydrophobic monomers which can be
utilized in preparing the aforementioned polyesters include
monofunctional alcohols such as hexanol, heptanol, octanol,
nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol,
pentadecanol, hexadecanol, heptadecanol, octadecanol, and other
alcohols, such as derived from about 6 to about 24 carbon atoms,
oleyl alcohol, linoleyl alcohol, cinnamyl alcohol, alkyl
substituted alcohols, such as 2-methylhexanol,
2,3,3-trimethylhexanol, 2-methyloctanol,
3,7-dimethyl-1,6-octadien-3-ol and the like, hydrophobic aromatic
monomers such as benzyl alcohol, monofunctional acids such as
hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid,
decanoic acid, stearic acid, lauric acid, palmitic acid, oleic
acid, linoleic acid, cinnamic acid, and other alkyl acids, such as
derived from about 4 to about 24 carbon atoms, benzoic acid,
naphthoic acid, mixtures thereof, and the like; and which
components can be employed in effective amounts of from about 0.1
mole percent to about 4.0 mole percent based on the starting diacid
or diester used to make the resin.
Additionally, crosslinking or branching agents can be utilized,
such as trifunctional or multifunctional monomers, which increase
the molecular weight and polydispersity of the polyester, and are
selected from the group consisting of glycerol, trimethylol ethane,
trimethylol propane, pentaerythritol, sorbitol, diglycerol,
trimellitic acid, trimellitic anhydride, pyromellitic acid,
pyromellitic anhydride, 1,2,4-cyctohexanetricarboxylic acid,
2,5,7-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic
acid, mixtures thereof, and the like; and which components can be
employed in effective amounts of from about 0.1 mole percent to
about 6.0 mole percent based on the starting diacid or diester used
to make the resin.
Numerous well known suitable pigments or dyes can be selected as
the colorant for the toner particles including, for example, carbon
black like REGAL 330.RTM., nigrosine dye, aniline blue,
phthalocyanines, magnetite, or mixtures thereof. A number of carbon
blacks available from, for example, Cabot Corporation can be
selected. The pigment, which is preferably carbon black, should be
present in a sufficient amount to render the toner composition
highly colored. Generally, the pigment particles are present in
amounts of from about 1 percent by weight to about 20 percent by
weight, and preferably from about 2 to about 10 weight percent
based on the total weight of the toner composition.
When the pigment particles are comprised of magnetites, thereby
enabling single component magnetic toners in some instances, which
magnetites are a mixture of iron oxides (FeO--Fe.sub.2 O.sub.3)
including those commercially available as MAPICO BLACK.RTM., they
are present in the toner composition in an amount of from about 10
percent by weight to about 80 percent by weight, and preferably in
an amount of from about 10 percent by weight to about 50 percent by
weight. Mixtures of carbon black and magnetite with from about 1 to
about 15 weight percent of carbon black, and preferably from about
2 to about 6 weight percent of carbon black, and magnetite, such as
MAPICO BLACK.RTM., in an amount of, for example, from about 5 to
about 60, and preferably from about 10 to about 50 weight percent
can be selected.
Charge additive examples include those as illustrated in U.S. Pat.
No. 4,338,390, the disclosure of which is totally incorporated
herein by reference, which additives can impart a positive charge
to the toner composition; the alkyl pyridinium compounds as
disclosed in U.S. Pat. No. 4,298,672, the disclosure of which is
totally incorporated herein by reference, and the charge control
additives as illustrated in U.S. Pat. Nos. 3,944,493; 4,007,293;
4,079,014; 4,394,430, and 4,560,635, which illustrates a toner with
a distearyl dimethyl ammonium methyl sulfate charge additive.
Negative charge additives can also be selected, such as zinc or
aluminum complexes, like an aluminum compound of a hydroxy
carboxylic acid (BONTRON E-88.RTM. from Orient Chemical Company),
the zinc complex of 3,5-ditertiary butyl salicylate (BONTRON
E-84.RTM. from Orient Chemical Company) and hydroxy bis
(3,5-ditertiary butyl salicylic) aluminate monohydrate (Alohas) and
the like.
There can be included in the toner compositions of the present
invention low molecular weight waxes, or mixtures thereof, such as
polypropylenes and polyethylenes such as EPOLENE N-15.TM.
commercially available from Eastman Chemical Products, Inc., VISCOL
550-P.TM., a low weight average molecular weight polypropylene
available from Sanyo Kasei K.K., and similar materials. The
commercially available polyethylenes selected have a molecular
weight of from about 1,000 to about 3000, such as those obtainable
from Petrolite Corporation, while the commercially available
polypropylenes utilized for the toner compositions of the present
invention are believed to have a molecular weight of from about
4,000 to about 5,000. Many of the polyethylene and polypropylene
compositions useful in the present invention are illustrated in
British Patent No. 1,442,835, the disclosure of which is totally
incorporated herein by reference. The low molecular weight wax
materials are present in the toner composition of the present
invention in various amounts, however, generally these waxes are
present in the toner composition in an amount of from about 1
percent by weight to about 15 percent by weight, and preferably in
an amount of from about 2 percent by weight to about 10 percent by
weight.
There can also be blended with the toner compositions of the
present invention other toner additives,.such as external additive
particles including flow aid additives, which additives are usually
present on the surface thereof. Examples of these additives include
metal oxides, such as aluminum oxide, titanium oxide, tin oxide,
cerium oxide mixtures thereof, and the like, colloidal fumed
silicas, such as AEROSIL.RTM., or Cabosil.RTM., metal salts and
metal salts of fatty acids including zinc stearate, magnesium
stearate, polymeric particles of from 0.2 to 5 microns such as
polyvinylidene fluoride which is obtainable from ATOCHEM North
America, Inc, polytetrafluoroethylene that is available from ICI
Advanced Materials, or polymeric microspheres of from 0.1 to 2.0
microns, such as those obtainable from Nippon Paint, Osaka, Japan,
and mixtures thereof, which additives are generally present in an
amount of from about 0.1 percent by weight to about 5 percent by
weight, and preferably in an amount of from about 0.1 percent by
weight to about 3 percent by weight. Several of the aforementioned
additives are illustrated in U.S. Pat. Nos. 3,590,000 and
3,800,588, the disclosures of which are totally incorporated herein
by reference.
With further respect to the present invention, colloidal silicas,
such as AEROSIL.RTM., can be surface treated with known charge
additives, such as DDAMS, in an amount of from about 1 to about 30
weight percent and preferably 10 weight percent, followed by the
addition thereof to the toner in an amount of from 0.1 to 10, and
preferably 0.1 to 1 weight percent.
Encompassed within the scope of the present invention are colored
toner and developer compositions comprised of toner resin particles
illustrated herein, and optional carrier particles, and as pigments
or colorants red, blue, green, brown, magenta, cyan and/or yellow
particles, as well as mixtures thereof. More specifically, with
regard to the generation of color images utilizing a developer
composition with the charge enhancing additives of the present
invention, illustrative examples of magenta materials that may be
selected as pigments include, for example, 2,9-dimethyl-substituted
quinacridone identified in the Color Index as CI 73915, Pigment Red
122, anthraquinone dye identified in the Color Index as CI 60710,
CI Dispersed Red 15, diazo dye identified in the Color Index as CI
26050, CI Solvent Red 19, and the like. Illustrative examples of
cyan materials that may be used as pigments include copper
tetra-4-(octadecyl sulfonamido) phthalocyanine, beta-copper
phthalocyanine pigment listed in the Color Index as CI 74160
Pigment Blue 15.3 and Anthrathrene Blue, identified in the Color
Index as CI 69810, Special Blue X-2137, and the like; while
illustrative examples of yellow pigments that may be selected are
diarylide yellow 3,3-dichlorobenzidene acetoacetanilides, a monoazo
pigment identified in the Color Index as CI 12700, CI Solvent
Yellow 16, a nitrophenyl amine sulfonamide identified in the Color
Index as Foron Yellow SE/GLN, CI Dispersed Yellow 33,
2,5-dimethoxy-4-sulfonanilide phenylazo-4'-chloro-2,5-dimethoxy
acetoacetanilide, and Permanent Yellow FGL. The aforementioned
pigments are incorporated into the toner composition in various
suitable effective amounts providing the objectives of the present
invention are achieved. In one embodiment, these colored pigment
particles are present in the toner composition in an amount of from
about 2 percent by weight to about 15 percent by weight calculated
on the weight of the toner resin particles.
For the formulation of developer compositions, there are mixed with
the toner particles carrier components, particularly those that are
capable of triboelectrically assuming an opposite polarity to that
of the toner composition. Accordingly, the carrier particles of the
present invention are selected to be of a negative or positive
polarity enabling the toner particles, which are oppositely
charged, to adhere to and surround the carrier particles.
Illustrative examples of carrier particles include iron powder,
steel, nickel, iron, ferrites, including copper zinc ferrites, and
the like. Additionally, there can be selected as carrier particles
nickel berry carriers as illustrated in U.S. Pat. No. 3,847,604,
the disclosure of which is totally incorporated herein by
reference. The selected carrier particles can be used with or
without a coating, the coating generally containing terpolymers of
styrene, methylmethacrylate, and a silane, such as triethoxy
silane, reference U.S. Pat. Nos. 3,526,533 and 3,467,634, the
disclosures of which are totally incorporated herein by reference;
polymethyl methacrylates; other known coatings; and the like. The
carrier particles may also include in the coating, which coating
can be present in one embodiment in an amount of from about 0.1 to
about 3 weight percent, conductive substances, such as carbon
black, in an amount of from about 5 to about 30 percent by weight.
Polymer coatings not in close proximity in the triboelectric series
can also be selected, reference U.S. Pat. Nos. 4,937,166 and
4,935,326, the disclosures of which are totally incorporated herein
by reference, including, for example, KYNAR.RTM. and
polymethylmethacrylate mixtures like 40/60. Coating weights can
vary as indicated herein; generally, however, from about 0.3 to
about 2, and preferably from about 0.5 to about 1.5 weight percent
coating weight is selected.
Furthermore, the diameter of the carrier particles, preferably
spherical in shape, is generally from about 35 microns to about
1,000 and preferably from about 50 to about 200 microns in
diameter, thereby permitting them to, for example, possess
sufficient density and inertia to avoid adherence to the
electrostatic images during the development process. The carrier
component can be mixed with the toner composition in various
suitable combinations, such as from about 1 to 5 parts per toner to
about 100 parts to about 200 parts by weight of carrier, are
selected.
The toner and developer compositions of the present invention may
be selected for use in electrostatographic imaging apparatuses
containing therein conventional photoreceptors providing that they
are capable of being charged negatively. Thus, the toner and
developer compositions of the present invention can be used with
layered photoreceptors that are capable of being charged
negatively, or positively, such as those described in U.S. Pat. No.
4,265,990, the disclosure of which is totally incorporated herein
by reference. Illustrative examples of inorganic photoreceptors
that may be selected for imaging and printing processes include
selenium; selenium alloys, such as selenium arsenic, selenium
tellurium and the like; halogen doped selenium substances; and
halogen doped selenium alloys. Other similar photoreceptors can be
selected providing the objectives of the present invention are
achievable.
The toner compositions are usually jetted and classified subsequent
to preparation to enable toner particles with a preferred average
diameter of from about 5 to about 25 microns, and more preferably
from about 6 to about 12 microns. Also, the toner compositions of
the present invention preferably possess a triboelectric charge of
from about 5 to 40 microcoulombs per gram in embodiments thereof as
determined by the known charge spectograph. Admix time for the
toners of the present invention are preferably from about 15
seconds to 1 minute, and more specifically, from about 15 to about
30 seconds in embodiments thereof as determined by the known charge
spectograph. These toner compositions with rapid admix
characteristics enable, for example, the development of latent
electrostatographic images in electrophotographic imaging
apparatuses, which developed images have substantially no
background deposits thereon, even at high toner dispensing rates in
some instances, for instance exceeding 20 grams per minute; and
further, such toner compositions can be selected for high speed
electrophotographic apparatuses, that is those exceeding 70 copies
per minute.
The following Examples are being supplied to further define various
species of the present invention, it being noted that these
Examples are intended to illustrate and not limit the scope of the
present invention. Parts and percentages are by weight unless
otherwise indicated.
EXAMPLE I
Poly(1,2-propylene terephthalate-co-diethylene terephthalate) end
blocked with stearate with an average molecular weight of 10,500
grams per mole and having a diethylene/1,2-propylene molar ratio of
15:85, respectively, and end blocked with a stearate group was
prepared as follows.
A 7.6 liter Parr reactor equipped with a bottom drain valve, double
turbine agitator and distillation receiver with a cold water
condenser was charged with 3,250 grams of dimethylterephthalate,
2,369 grams of 1,2-propanediol, 267.91 grams of diethylene glycol,
51 grams of stearic acid, and 4.7 grams of butyltin oxide catalyst
obtained as FASCAT 4100.TM. from Elf Atochem North America, Inc.
The reactor was then heated to 165.degree. C. with stirring at 150
revolutions per minute and then heated to 200.degree. C. over a
duration of 6 hours, wherein the methanol byproduct (890 grams) was
collected via the distillation receiver to a container, and was
comprised of about 98 percent by volume of methanol and 2 percent
by volume of 1,2-propanediol as measured by the ABBE refractometer
available from American Optical Corporation. The mixture was then
maintained at 200.degree. C., and the pressure was reduced from
atmospheric to about 0.2 torr over a duration of about 3 hours.
During this time, there were further collected approximately 1,172
grams of glycol with about 97 percent by volume of 1,2-propanediol
and 3 percent by volume of methanol as measured by the ABBE
refractometer. (The theoretical yield of methanol is 1,072 grams,
and usually the transesterification is accomplished until about 980
to 1,000 grams of methanol, 93 percent conversion). The reactor was
then purged with nitrogen to atmospheric pressure, and the polymer
discharged through the bosom drain onto a container cooled with dry
ice to yield 3.65 kilograms of poly(1,2-propylene
terephthalate-co-diethylene terephthalate) end blocked with
stearate resin. The aforementioned resin product glass transition
temperature was measured to be 57.degree. C. (onset) utilizing the
910 Differential Scanning Calorimeter available from E. I. DuPont
operating at a heating rate of 10.degree. C. per minute. The number
average molecular weight of the polyester product resin was
measured to be 6,000 grams per mole and the weight average
molecular weight was measured to be 10,500 grams per mole using
tetrahydrofuran as the solvent and obtained with the 700 Satellite
WISP gel permeation chromatograph available from Waters Company
equipped with a styrogel column. 1.8 Grams of the
poly(1,2-propylene terephthalate-co-diethylene terephthalate) end
blocked with stearate resin were then pressed into a pellet of
about 1 centimeter in diameter and about 10 centimeters in length
using a press and die set supplied by Shimadzu with the Flowtester
500 series. The pressed sample pellet was then loaded in the
flowtester and subjected to standard Shimadzu conditions using 20
kilograms/cm.sup.2 load, and barrel temperature heated from
20.degree. C. to 130.degree. C. at a rate of 10.degree. C. per
minute. For the polyester resin of this Example, a softening point
of 78.degree. C., beginning of flow temperature T.sub.1 of
90.degree. C., and flow temperature T.sub.2 of 104.degree. C. were
obtained. The melt index of the resin of this Example was found to
be 9.3 grams per 10 minutes at 117.degree. C. with a loading of
2.16 kilograms. The acid number of the polyester resin was found to
be less than 1 milliequivalent per gram of potassium hydroxide.
EXAMPLE II
Poly(1,2-propylene terephthalate-co-diethylene terephthalate) end
blocked with stearate with an average molecular weight of 15,600
grams per mole and having a diethylene/1,2-propylene molar ratio of
15:85, respectively, and end blocked with a stearate group was
prepared as follows.
A 7.6 liter Parr reactor equipped with a bottom drain valve, double
turbine agitator and distillation receiver with a cold water
condenser was charged with 3,250 grams of dimethylterephthalate,
2,369 grams of 1,2-propanediol (1 equivalent excess), 267.91 grams
of diethylene glycol, 51 grams of stearic acid, and 4.7 grams of
butyltin oxide catalyst obtained as FASCAT 4100.TM. from Elf
Atochem North America, Inc. The reactor was then heated to
165.degree. C. with stirring at 150 revolutions per minute and then
heated to 200.degree. C. over a duration of 6 hours, wherein the
methanol byproduct (805 grams) was collected via the distillation
receiver to a container comprised of about 98 percent by volume of
methanol and 2 percent by volume of 1,2-propanediol as measured by
the ABBE refractometer available from American Optical Corporation.
The mixture was then maintained at 200.degree. C., and the pressure
was reduced from atmospheric to about 0.2 torr over a duration of
about 3 hours. During this time, there was further collected
approximately 1,237 grams of glycol with about 97 percent by volume
of 1,2-propanediol and 3 percent by volume of methanol as measured
by the ABBE refractometer. The reactor was then purged with
nitrogen to atmospheric pressure, and the polymer discharged
through the bottom drain onto a container cooled with dry ice to
yield 3.65 kilograms of poly(1,2-propylene
terephthalate-co-diethylene terephthalate) end blocked with
stearate resin. The resin glass transition temperature was measured
to be 61.degree. C. (onset) utilizing the 910 Differential Scanning
Calorimeter available from DuPont operating at a heating rate of
10.degree. C. per minute. The number average molecular weight was
measured to be 7,700 grams per mole and the weight average
molecular weight was measured to be 15,600 grams per mole using
tetrahydrofuran as the solvent and obtained with the 700 Satellite
WISP gel permeation chromatograph available from Waters Company
equipped with a styrogel column. The melt index of the resin of
this Example was found to be 2.0 grams per 10 minutes at
117.degree. C. with a loading of 2.16 kilograms. The acid number of
the polyester resin was found to be less than 1 milliequivalent per
gram of potassium hydroxide.
EXAMPLE III
Poly(1,2-propylene terephthalate-co-diethylene
terephthalate-co-1,1,1-trimethylene propane terephthalate) end
blocked with stearate with an average molecular weight of 41,700
grams per mole and having a diethylene/1,2-propylene molar ratio of
25:75, respectively, trimethylolpropane as branching agent and end
blocked with a stearate group was prepared as follows.
A 7.6 liter Parr reactor equipped with a bottom drain valve, double
turbine agitator and distillation receiver with a cold water
condenser was charged with 3,250 grams of dimethylterephthalate,
2,228.8 grams of 1,2-propanediol (1 equivalent excess), 443.1 grams
of diethylene glycol, 47.5 grams of stearic acid, 44.8 grams of
trimethylol propane and 4.7 grams of butyltin oxide catalyst
obtained as FASCAT 4100.TM. from Elf Atochem North America, Inc.
The reactor was then heated to 165.degree. C. with stirring at 150
revolutions per minute and then heated to 200.degree. C. over a
duration of 6 hours, wherein the methanol byproduct (800 grams) was
collected via the distillation receiver to a container comprised of
about 98 percent by volume of methanol and 2 percent by volume of
1,2-propanediol as measured by the ABBE refractometer available
from American Optical Corporation. The mixture was then maintained
at 200.degree. C., and the pressure was reduced from atmospheric to
about 0.2 torr over a duration of about 3 hours. During this time,
there were further collected approximately 1,300 grams of
distillate in the distillation receiver comprised of approximately
97 percent by volume of 1,2-propanediol and 3 percent by volume of
methanol as measured by the ABBE refractometer. The pressure was
then further maintained at about 0.2 torr, and the temperature of
the reaction mixture increased to 210.degree. C. for an additional
2 hours, wherein an additional 27 grams of 1,2-propanediol were
collected. The reactor was then purged with nitrogen to atmospheric
pressure, and the polymer discharged through the bottom drain onto
a container cooled with dry ice to yield 3.7 kilograms of
poly(1,2-propylene terephthalate-co-diethylene
terephthalate-co-1,1,1-trimethylene propane terephthalate) end
blocked with stearate resin. The resin glass transition temperature
was measured to be 58.degree. C. (onset) utilizing the 910
Differential Scanning Calorimeter available from E. I. DuPont
operating at a heating rate of 10.degree. C. per minute. The number
average molecular weight was measured to be 10,900 grams per mole
and the weight average molecular weight was measured to be 41,700
grams per mole using tetrahydrofuran as the solvent and obtained
with the 700 Satellite WISP gel permeation chromatograph available
from Waters Company equipped with a styrogel column. 1.8 Grams of
the poly(1,2-propylene terephthalate-co-diethylene
terephthalate-co-1,1,1-trimethylene propane terephthalate) end
blocked with stearate resin were then pressed into a pellet of
about 1 centimeter in diameter and about 10 centimeters in length
using a press and die set supplied by Shimadzu with the Flowtester
500 series. The pressed sample pellet was then loaded in the
flowtester and subjected to standard Shimadzu conditions using 20
kilograms/cm.sup.2 load, and barrel temperature heated from
20.degree. C. to 130.degree. C. at a rate of 10.degree. C. per
minute. For the resin of this Example, a softening point of
80.degree. C., beginning of flow temperature T.sub.1 of 97.degree.
C., and flow temperature T.sub.2 of 105.degree. C. were obtained.
The melt index of the resin of this Example was found to be 10.1
grams per 10 minutes at 117.degree. C. with a loading of 16.6
kilograms. The acid number of the polyester resin was found to be
less than 1 milliequivalent per gram of potassium hydroxide.
EXAMPLE IV
Poly(1,2-propylene terephthalate-co-diethylene
terephthalate-co-1,1,1-trimethylene propane terephthalate) end
blocked with stearate with an average molecular weight of 38,300
grams per mole and having a diethylene/1,2-propylene molar ratio of
25:75, respectively, trimethylolpropane as branching agent and
terminated with a stearyl end group was prepared as follows.
A 7.6 liter Parr reactor equipped with a bottom drain valve, double
turbine agitator and distillation receiver with a cold water
condenser was charged with 3,250 grams of dimethylterephthalate,
2,228.8 grams of 1,2-propanediol (1 equivalent excess), 443.1 grams
of diethylene glycol, 47.5 grams of stearic acid, 44.8 grams of
trimethylol propane and 4.7 grams of butyltin oxide catalyst
obtained as FASCAT 4100.TM. from Elf Atochem North America, Inc.
The reactor was then heated to 165.degree. C. with stirring at 150
revolutions per minute and then heated to 200.degree. C. over a
duration of 6 hours, wherein the methanol byproduct (809 grams) was
collected via the distillation receiver to a container comprised of
about 98 percent by volume of methanol and 2 percent by volume of
1,2-propanediol as measured by the ABBE refractometer available
from American Optical Corporation. The mixture was then maintained
at 200.degree. C., and the pressure was reduced from atmospheric to
about 0.2 torr over a duration of about 3 hours. During this time,
there were further collected approximately 1,350 grams of
distillate in the distillation receiver comprised of approximately
97 percent by volume of 1,2-propanediol and 3 percent by volume of
methanol as measured by the ABBE refractometer. The pressure was
then further maintained at about 0.2 torr and the temperature of
the reaction mixture increased to 210.degree. C. for an additional
2 hours, wherein an additional 27 grams of 1,2-propanediol were
collected. The reactor was then purged with nitrogen to atmospheric
pressure, and the polymer discharged through the bottom drain onto
a container cooled with dry ice to yield 3.7 kilograms of
poly(1,2-propylene terephthalate-co-diethylene
terephthalate-co-1,1,1-trimethylene propane terephthalate) end
blocked with stearate resin. The resin glass transition temperature
was measured to be 57.5.degree. C. (onset) utilizing the 910
Differential Scanning Calorimeter available from DuPont operating
at a heating rate of 10.degree. C. per minute. The number average
molecular weight was measured to be 10,000 grams per mole and the
weight average molecular weight was measured to be 38,300 grams per
mole using tetrahydrofuran as the solvent and obtained with the 700
Satellite WISP gel permeation chromatograph available from Waters
Company equipped with a styrogel column. 1.8 Grams of the
poly(1,2-propylene terephthalate-co-diethylene
terephthalate-co-1,1,1-trimethylene propane terephthalate) end
blocked with stearate resin were then pressed into a pellet of
about 1 centimeter in diameter and about 10 centimeters in length
using a press and die set supplied by Shimadzu with the Flowtester
500 series. The melt index of the resin of this Example was found
to be 20.3 grams per 10 minute at 117.degree. C. with a loading of
16.6 kilograms. The acid number of the polyester resin was found to
be less than 1 milliequivalent per gram of potassium hydroxide.
COMPARATIVE EXAMPLE V
Poly(1,2-propylene terephthalate-co-diethylene
terephthalate-co-1,1,1-trimethylene propane terephthalate) resin
with an average molecular weight of 34,000 grams per mole and
having a diethylene/1,2-propylene molar ratio of 25:75,
respectively, and note that with no hydrophobic end groups are
present, was prepared as follows.
A 7.6 liter Parr reactor equipped with a bottom drain valve, double
turbine agitator and distillation receiver with a cold water
condenser was charged with 3,250 grams of dimethylterephthalate,
2,228.8 grams of 1,2-propanediol (1 equivalent excess), 443.1 grams
of diethylene glycol, 44.8 grams of trimethylol propane and 4.7
grams of butyltin oxide catalyst obtained as FASCAT 4100.TM. from
Elf Atochem North America, Inc. The reactor was then heated to
165.degree. C. with stirring at 150 revolutions per minute and then
heated to 200.degree. C. over a duration of 6 hours, wherein the
methanol byproduct (809 grams) was collected via the distillation
receiver to a container comprised of about 98 percent by volume of
methanol and 2 percent by volume of 1,2-propanediol as measured by
the ABBE refractometer available from American Optical Corporation.
The mixture was then maintained at 200.degree. C., and the pressure
was reduced from atmospheric to about 0.2 torr over a duration of
about 3 hours. During this time, there were further collected
approximately 1,240 grams of distillate in the distillation
receiver comprised of approximately 97 percent by volume of
1,2-propanediol and 3 percent by volume of methanol as measured by
the ABBE refractometer. The pressure was then further maintained at
about 0.2 torr and the temperature of the reaction mixture
increased to 210.degree. C. for an additional 2 hours, wherein an
additional 30 grams of 1,2-propanediol were collected. The reactor
was then purged with nitrogen to atmospheric pressure, and the
polymer discharged through the bottom drain onto a container cooled
with dry ice to yield 3.7 kilograms of poly(1,2-propylene
terephthalate-co-diethylene terephthalate-co-1,1,1-trimethylene
propane terephthalate) resin. The resin glass transition
temperature was measured to be 57.2.degree. C. (onset) utilizing
the 910 Differential Scanning Calorimeter available from DuPont
operating at a heating rate of 10.degree. C. per minute. The number
average molecular weight was measured to be 10,100 grams per mole
and the weight average molecular weight was measured to be 34,000
grams per mole using tetrahydrofuran as the solvent and obtained
with the 700 Satellite WISP gel permeation chromatograph available
from Waters Company equipped with a styrogel column. 1.8 Grams of
the poly(1,2-propylene terephthalate-co-diethylene
terephthalate-co-1,1,1-trimethylene propane terephthalate) resin
were then pressed into a pellet of about 1 centimeter in diameter
and about 10 centimeters in length using a press and die set
supplied by Shimadzu with the Flowtester 500 series. The melt index
of the resin of this Example was found to be 17 grams per 10 minute
at 117.degree. C. with a loading of 16.6 kilograms. The acid number
of the polyester resin was found to be 16 milliequivalent per gram
of potassium hydroxide.
EXAMPLE VI
A toner composition comprised of 95 percent by weight of the
polyester resin of Example II and 5 percent by weight of REGAL
330.RTM. pigment was prepared as follows.
The polyester resin of Example II was ground to about 500 microns
average volume diameter in a Model J Fitzmill equipped with an 850
micrometer screen. After grinding, 950 grams (95 percent by weight
of toner) of the polyester polymer were mixed with 50 grams of
REGAL 330.RTM. carbon black pigment (5 percent by weight of toner).
The two components were dry blended first on a paint shaker and
then on a roll mill. A Davo twin screw extruder was then used to
melt mix the aforementioned mixture at a barrel temperature of
140.degree. C., screw rotational speed of 50 rpm and at a feed rate
of 20 grams per minute. The extruded strands were broken into
coarse particles utilizing a coffee bean grinder available from
Black and Decker. An 8 inch Sturtevant micronizer was used to
reduce the particle size further. After grinding, the toner was
measured to display an average volume diameter particle size of 9.1
microns with a geometric distribution of 1.43 as measured by the
Coulter Counter. The resulting toner was then utilized without
further classification.
A developer composition was prepared by roll milling the
aforementioned toner, 3 parts by weight, with 100 parts by weight
of a 90 micron diameter ferrite carrier core with a coating, 0.55
percent by weight of a polymer of methylmethacrylate (80.4
percent), vinyl triethoxysilane (5 percent) and styrene (14.1
percent). The tribo data was obtained using the known blow-off
Faraday Cage apparatus. Toner developer was subjected to 80 percent
humidity in a chamber for 48 hours at 80.degree. F. to result in a
triboelectric charge of -15 microcoulombs per gram, and at 20
percent humidity level in a chamber for 48 hours at 60.degree. F.
to result in a triboelectric charge of -33 microcoulombs per gram.
The ratio of the corresponding triboelectric charge at 20 percent
RH to 80 percent RH as given by Equation 1 was measured to be 2.2.
Unfused copies were then produced using a custom made imaging
apparatus similar to the Xerox Corporation 9200 imaging apparatus
with the fusing system disabled. The unfused copies were then fused
in the 1075 fuser. Fusing evaluation of the toner indicated a
minimum fixing temperature of about 129.degree. C., and hot-offset
temperature of 170.degree. C.
EXAMPLE VII
A toner composition comprised of 91 percent by weight of the
polyester resin of Example III, 5 percent by weight of REGAL
330.RTM. pigment, and 4 percent by weight of 660P wax available
from SANYO KASEI K.K. was prepared as follows.
The polyester resin of Example III was ground to about 500 microns
average volume diameter in a Model J Fitzmill equipped with an 850
micrometer screen. After grinding, 910 grams of polymer were mixed
with 50 grams of REGAL 330.RTM. pigment and 40 grams of 660P
polypropylene wax. The three components were dry blended first on a
paint shaker and then on a roll mill. A Davo twin screw extruder
was then used to melt mix the aforementioned mixture at a barrel
temperature of 140.degree. C., screw rotational speed of 50 rpm and
at a feed rate of 20 grams per minute. The extruded strands were
broken into coarse particles utilizing a coffee bean grinder
available from Black and Decker. An 8 inch Sturtevant micronizer
was used to reduce the particle size further. After grinding, the
toner was measured to display an average volume diameter particle
size of 8.5 microns with a geometric distribution of 1.43 as
measured by the Coulter Counter. The resulting toner was then
utilized without further classification. A developer composition
was prepared by roll milling the aforementioned toner, 3 parts by
weight with 100 parts by weight of the carrier of Example VI. The
tribo data was obtained using the known blow-off Faraday Cage
apparatus, and the toner developer was subjected to 20 percent
humidity in a chamber for 48 hours at 60.degree. F. to result in a
triboelectric charge of -37 microcoulombs per gram, and at 80
percent humidity level in a chamber for 48 hours at 80.degree. F.
to result in a triboelectric charge of -17 microcoulombs per gram.
The ratio of the corresponding triboelectric charge at 20 percent
RH to 80 percent RH as given by Equation 1 was measured to be 2.18.
Unfused copies were then produced with the imaging apparatus of
Example VI with the fusing system disabled. The unfused copies were
then fused with a Xerox Corporation 1075 fuser. Fusing evaluation
of the toner indicated a minimum fixing temperature of about
133.degree. C., and hot-offset temperature of 165.degree. C.
EXAMPLE VIII
A toner composition comprised of 95 percent by weight of the
polyester resin of Example IV and 5 percent by weight of REGAL
330.RTM. pigment was prepared as follows.
The polyester resin of Example IV was ground to about 500 microns
average volume diameter in a Model J Fitzmill equipped with an 850
micrometer screen. After grinding, 950 grams (95 percent by weight
of toner) of polymer were mixed with 50 grams of REGAL 330.RTM.
pigment (5 percent by weight of toner). The two components were dry
blended first on a paint shaker and then on a roll mill. A Davo
twin screw extruder was then used to melt mix the aforementioned
mixture at a barrel temperature of 140.degree. C., screw rotational
speed of 50 rpm and at a feed rate of 20 grams per minute. The
extruded strands were broken into coarse particles utilizing a
coffee bean grinder available from Black and Decker. An 8 inch
Sturtevant micronizer was used to reduce the particle size further.
After grinding, the toner was measured to display an average volume
diameter particle size of 8.5 microns with a geometric distribution
of 1.45 as measured by the Coulter Counter. The resulting toner was
then utilized without further classification. A developer
composition was prepared by roll milling the aforementioned toner,
3 parts by weight with 100 parts by weight of the carrier of
Example VI. The tribo data was obtained using the known blow-off
Faraday Cage apparatus, and the toner developer was subjected to 20
percent humidity in a chamber for 48 hours at 60.degree. F. to
result in a triboelectric charge of -30 microcoulombs per gram, and
at 80 percent humidity level in a chamber for 48 hours at
80.degree. F. to result in a triboelectric charge of -15
microcoulombs per gram. The ratio of the corresponding
triboelectric charge at 20 percent RH to 80 percent RH as given by
Equation 1 was measured to be 2.0. Unfused copies were then
produced with the imaging apparatus of Example VI with the fusing
system disabled. The unfused copies were subsequently fused in a
Xerox Corporation 1075 fuser. Fusing evaluation of the toner
indicated a minimum fixing temperature of about 129.degree. C., and
hot-offset temperature of 165.degree. C.
COMPARATIVE EXAMPLE IX
A toner composition comprised of 91 percent by weight of the
polyester resin of Comparative Example V, 5 percent by weight of
REGAL 330.RTM. pigment, and 4 percent by weight of 660P
polypropylene wax was prepared as follows.
The polyester resin of Example V was in the form of a large chunk.
The resulting polymer was ground to about 500 microns average
volume diameter in a Model J Fitzmill equipped with an 850
micrometer screen. After grinding, 910 grams of polymer were mixed
with 50 grams of REGAL 330.RTM. pigment and 40 grams of 660P wax.
The three components were dry blended first on a paint shaker and
then on a roll mill. A Davo twin screw extruder was then used to
melt mix the aforementioned mixture at a barrel temperature of
140.degree. C., screw rotational speed of 50 rpm and at a feed rate
of 20 grams per minute. The extruded strands were broken into
coarse particles utilizing a coffee bean grinder available from
Black and Decker. An 8 inch Sturtevant micronizer was used to
reduce the particle size further. After grinding, the toner was
measured to display an average volume diameter particle size of 7.9
microns with a geometric distribution of 1.39 as measured by the
Coulter Counter. The resulting toner was then utilized without
further classification. A developer composition was prepared by
roll milling the aforementioned toner, 3 parts by weight with 100
parts by weight of the carrier of Example VI. The tribo data was
obtained using the known blow-off Faraday Cage apparatus, and the
toner developer was subjected to 20 percent humidity in a chamber
for 48 hours at 60.degree. F. to result in toner triboelectric
charge of -60 microcoulombs per gram, and at 80 percent humidity
level in a chamber for 48 hours at 80.degree. F. to result in toner
triboelectric charge of -15 microcoulombs per gram. The ratio of
the corresponding triboelectric charge at 20 percent RH to 80
percent RH as given by Equation I was measured to be 4.0. In
comparison to the toner compositions of Examples VI, VII, and VIII,
the RH sensitivity of this Example was much higher because no
hydrophobic end group was present. Unfused copies were then
produced with the imaging apparatus with the fusing system
disabled. The unfused copies were then subsequently fused with the
Xerox Corporation 1075 fuser. Fusing evaluation of the toner
indicated a minimum fixing temperature of about 135.degree. C., and
hot-offset temperature of 170.degree. C.
EXAMPLE X
A toner composition comprised of 98 percent by weight of the
polyester resin of Example I and 2 percent by weight of PV FAST
BLUE.TM. pigment was prepared as follows.
The polyester resin of Example I was to about 500 microns average
volume diameter in a Model J Fitzmill equipped with an 850
micrometer screen. After grinding, 980 grams (98 percent by weight
of toner) of polymer were mixed with 20 grams of PV FAST BLUE.TM.
pigment (2 percent by weight of toner). The two components were dry
blended first on a paint shaker and then on a roll mill. A Davo
twin screw extruder was then used to melt mix the aforementioned
mixture at a barrel temperature of 120.degree. C., screw rotational
speed of 50 rpm, and at a feed rate of 25 grams per minute. The
extruded strands were broken into coarse particles utilizing a
coffee bean grinder available from Black and Decker. An 8 inch
Sturtevant micronizer was used to reduce the particle size further.
After grinding, the toner was measured to display an average volume
diameter particle size of 6.9 microns with a geometric distribution
of 1.37 as measured by the Coulter Counter. The resulting toner was
then utilized without further classification. A developer
composition was prepared by roll milling the aforementioned toner,
3 parts by weight, with 100 parts by weight of the carrier of
Example VI. The tribo data was obtained using the known blow-off
Faraday Cage apparatus, and the toner developer was subjected to 20
percent humidity in a chamber for 48 hours at 60.degree. F. to
result in a triboelectric charge of 16 microcoulombs per gram, and
at 80 percent humidity level in a chamber for 48 hours at
80.degree. F. to result in a triboelectric charge of 8
microcoulombs per gram. The ratio of the corresponding
triboelectric charge at 20 percent RH to 80 percent RH as given by
Equation 1 was measured to be 2.0. Unfused copies were then
produced with the imaging apparatus of Example VI with the fusing
system disabled. The unfused copies were then subsequently fused
with the Xerox Corporation MAJESTIK.TM. color fuser. Fusing
evaluation of the toner indicated a minimum fixing temperature of
about 135.degree. C., and hot-offset temperature of 170.degree.
C.
Other embodiments and modifications of the present invention may
occur to those of skill in this art subsequent to a review of the
present application and the information presented herein; these
embodiments and modifications, as well as equivalents thereof, are
also included within the scope of this invention.
* * * * *